Why would you need it? If it is a sanctioned event, there should be safety/rescue personnel at the ready.
My understanding is the swim safety device is for use when there aren't personnel nearby watching you or to give lifeguards/shore observers a hint where you are in the water.
I don't care what anyone says, I'm not swimming in Lake Michigan without my personal safety device
www.usms.org/.../picture.php
Hahahaha! You are a funny girl Amanda!